In Chemical Abstracts 69: 867765 (citing Julia, M. et al., Bull. Soc. Chim. Fr. 1968, (3), 1000-7) compounds under the general formula ##STR2## are described. Among the compounds mentioned are compounds wherein R.sup.I represents m-OCH.sub.3 and R.sup.II represents H, CH.sub.3, C.sub.2 H.sub.5, CH.sub.2 C.sub.6 H.sub.5, CH.sub.2 CH.sub.2 C.sub.6 H.sub.5 or CH.sub.2 CH.sub.2 C.sub.6 H.sub.4 NO .sub.2 (p) and wherein R.sup.I represents m--OH and R.sup.II represents CH.sub.2 CH.sub.2 C.sub.6 H.sub.5 or CH.sub.2 CH.sub.2 C.sub.6 H.sub.4 NO.sub.2 (p). Said compounds were prepared for investigation of pharmacological properties.
Swiss Patent No. 526,536 describes compounds under the formula ##STR3## wherein R.sup.I represents H or OH and R.sup.II represents H. The compounds are claimed to have useful pharmacological properties especially as broncholytic agents.
DE Offenlegungschrift 2 621 536 describes compounds of the formula ##STR4## wherein X.sup.I is hydrogen or an acyl group and R.sup.I is an alkyl, alkenyl or phenylalkyl group The compounds are claimed to have dopaminergic properties.
EP-Al-0030526 and Hacksell et al. in J. Med. Chem., vol. 24, p. 1475-1482 (1981) describe compounds of the formula ##STR5## wherein n is 1 or 2, Y is OH, R.sup.1 COO, R.sup.2 R.sup.3 NCOO--or R.sup.4 O whereby R.sup.1 is an alkyl group having 1-5 carbon atoms or a possibly substituted phenyl group, R.sup.2 is an alkyl group having 1-5 carbon atoms, a phenethyl, benzyl or phenyl group, R.sup.3 is H or an alkyl group having 1-5 carbon atoms, and R.sup.4 is an allyl or benzyl group, and R is an alkyl group having 1-5 carbon atoms, a hydroxyalkyl, dimethylaminoalkyl or methylthioalkyl group having 2-6 carbon atoms in the alkyl part and having the heteroatom bound in a position other than the 1 position, or an alkenyl group having 3-5 carbon atoms other than a 1-alkenyl group, as bases and pharmaceutically acceptable acid addition salts thereof, which compounds are potent neuropharmacological agents. Thus said compounds are active as presynaptic dopamine receptor agonists when administered to animals including man. Said compounds are thus useful for treatment of disorders in the central nervous system, especially psychotic disorders in man.
In particular compounds of the above formula wherein R represents n-propyl are described. EP-Al-0030526 refers to and covers in general the pure enantiomers as well as mixtures thereof. However, the enantiomers are not specifically disclosed.
In Acta Pharmaceutica Suecica Suppl. 1983:1 p. 130-137 and 145-153 the pharmacological properties of the (-) and (+) enantiomers of the compound ##STR6## are described.
In European Patent Application No. 83850084.1, enantiomers of compounds of the formula ##STR7## are described wherein Y is OH, R.sup.1 COO, R.sup.2 R.sup.3 NCOO or R.sup.4 O. In compounds wherein Y is R.sup.2 R.sup.3 NCOO R.sup.2 is hydrogen, an alkyl group having 1-5 carbon atoms, a phenethyl, benzyl or phenyl group which may be mono- or disubstituted in the aromatic part with a methyl, methoxy, hydroxy, nitro or cyano group or a halogen, R.sup.3 is H, an alkyl group having 1 to 5 carbon atoms or a phenyl group or R.sup.2 and R.sup.3 together with the nitrogen atom form a 5, 6 or 7 membered ring that may contain 1 to 3 double bonds and/or 1 or 2 further heteroatoms selected from N, O and S. Specifically described in either of the two European patent applications above is i.a. a compound wherein Y is ##STR8##